Kaneohe and Waimanalo streams on the windward side of the island of Oahu in the Hawaiian Islands have been hardened to prevent flooding. The hardening process has involved elimination of the natural riparian habitat and replacement of the natural stream channel with a concrete-lined conduit having vertical walls and a broad, flat bottom. The shallow depth of the water column and the absence of shade have resulted in temperatures that average as much as 4-5oC above ambient and rise as high as 32oC during daylight hours. Unlike most low-order streams, the hardened sections of both streams are autotrophic, as evidenced by elevated pH values and O2 concentrations as high as 150% of saturation. Several allochthonous inputs, one from a storm sewer and the other from a natural spring, introduced water with anomalously low O2 concentrations and very high nitrate concentrations. The absence of sediments in the hardened sections of the streams precludes natural sedimentary microbial processes, including denitrification. Nitrate concentrations in a section of Waimanalo Stream with a natural streambed drop dramatically from values in excess of 400 ?M to concentrations less than 10 ?M at the head of the estuary. Although some of this decline is due to dilution with seawater, the concentration of nitrate at the head of the estuary is only 10% of the value that could be explained by dilution effects. Biological processes associated with a natural streambed thus appear very important to the functionality of the streams and in particular to their ability to process allochthonous nutrient inputs in a way that minimizes impacts on the nearshore environment. Prevention of flooding can be accomplished by mechanisms that do not involve elimination of riparian buffer zones and destruction of channel habitat. To maintain water quality and stream functionality, it will be important that these alternative methods of flood control be utilized. Converting natural streams to storm sewers is an unenlightened way to address flooding problems.

HTTPS(download)Navigate directly to the URL for data access and direct download.

FTP(download)These data are available through the File Transfer Protocol (FTP). You may use any FTP client to download these data.

Distribution Formats

Microsoft Excel

Microsoft Word

CSV

ASCII Text

Ordering Instructions

Data may be searched and downloaded using online services provided by NCEI using the online resource URLs in this record. Contact NCEI Information Services for custom orders. When requesting data from NCEI, the desired data set may be referred to by the unique package identification number listed in this metadata record.

Quantify the effects of stream hardening on water quality and stream functionality and the effects on the near shore coral ecosystem.

Use Limitations

accessLevel: Public

Distribution liability: NOAA and NCEI make no warranty, expressed or implied, regarding these data, nor does the fact of distribution constitute such a warranty. NOAA and NCEI cannot assume liability for any damages caused by any errors or omissions in these data. If appropriate, NCEI can only certify that data it distributes are an authentic copy of the records that were accepted for inclusion in the NCEI archives.

NOAA and NCEI cannot provide any warranty as to the accuracy, reliability, or completeness of furnished data. Users assume responsibility to determine the usability of these data. The user is responsible for the results of any application of this data for other than its intended purpose.

Fees

Digital data may be downloaded from NCEI at no charge in most cases. For custom orders of digital data or to obtain a copy of analog materials, please contact NCEI Information Services for information about current fees.

2015-04-22T00:00:00 - NOAA created the National Centers for Environmental Information (NCEI) by merging NOAA's National Climatic Data Center (NCDC), National Geophysical Data Center (NGDC), and National Oceanographic Data Center (NODC), including the National Coastal Data Development Center (NCDDC), per the Consolidated and Further Continuing Appropriations Act, 2015, Public Law 113-235. NCEI launched publicly on April 22, 2015.